Prostaglandins are primarily local or tissue hormones which have their effects at or near the site of release and are metabolized before reaching the arterial circulation. A possible exception is prostaglandin A-2, which has been proposed as a circulating hormone; however, there is no evidence that prostaglandin A-2 is biosynthesized in the mammalian kidney or even in extrarenal tissues. The prostaglandin generated and released in the kidney is predominantly E-2. Some blood vessels also synthesize prostaglandins intramurally, where their local release influences vascular tone and reactivity. Endogenous prostaglandin E-2 production contributes to the regulation of blood pressure by (1) opposing the vasoconstrictor and antidiuretic actions of circulating pressor hormones; (2) braking the release of norepinephrine from vasoconstrictor nerves; and (3) participating in the control extracellular fluid volume through its renal hemodynamic actions.
- Copyright © 1975 by American Heart Association